I. Field of the Invention.
The present invention relates generally to the field of exercise equipment. More particularly, the present invention relates to an apparatus which safely self-spots a weightlifter exercising with barbell or dumbbell assemblies.
II. Description of the Related Art.
Athletes of many disciplines, including weightlifters, improve their strength and endurance by including weight training within their workout regimens. It is generally recognized that superior results occur when the athlete, or lifter, utilizes free weights in the weight training program, which provide the lifter with full range of motion and control. One common and effective program for lifters to increase overall muscle strength is to repetitively lift a predetermined weight for a predetermined number of sets. For maximum body muscle strength, the lifter attempts to exert all of his or her strength on the last one or two repetitions of each set. Another popular and effective program is for the lifter to repetitively lift a predetermined weight until the lifter""s muscles reach a point of almost complete exhaustion. However, for the lifter to safely utilize either program with free weights, it is both desirable and generally necessary for the lifter to engage the assistance of one or more spotters to observe the lifter during his or her exercise program. The spotters help lift and remove the weight when the lifter no longer has sufficient strength or energy to place the weight back to a stored position, typically on support arms of a weight support or a weight bench. Conducting these programs without a spotter is extremely dangerous to the lifter. Muscle exertion and exhaustion may cause the lifter to lose control of the weights, leading to the weights being uncontrollably dropped onto and injuring the lifter. Commonly, the lifter is unable to obtain a spotter before commencing the repetitive weight lifting programs of these types. As a result, the lifter is faced with the dilemma of either ignoring proper safety procedures and conducting the weight lifting exercises without the use of spotters or not conducting the weight lifting program altogether. This dilemma can occur whether the lifter utilizes dumbbells or weights removably mounted on a barbell.
The weightlifting industry developed various devices that utilize motors to lift a weighted barbell for a lifter and eliminate the need for spotters. Typically, these devices have two movable cables traveling on respective, spaced-apart pulleys located at fixed positions on a frame. Distal ends of the cables are connected to the barbell, and proximal ends of the cables are operably connected to a single motor. The barbell is raised and lowered by respectively retracting and extending the cables by the motor. However, the motor must be activated for the cables to retract or extend, and the cables either extend or retract together, but not independently. Examples of such devices are described in U.S. Pat. Nos. 4,949,959 and 5,048,826.
To provide independent travel of the cables, the weightlifting industry developed devices which utilize a separate motor for each cable. For example, each cable retracts and extends from a drum which is operably mounted to a motor, as shown in U.S. Pat. No. 4,998,721. Although each motor can actuate independently of the other, the motors are under constant low-level actuation to maintain tension on the cables, which requires the use of sensors. Also, since the cables respectively suspend from drums located at fixed positions with respect to the frame, the distance between the cables cannot be varied to accommodate different sized barbells or permit the use of dumbbells as xe2x80x9cfree-weightsxe2x80x9d with the cables traveling along a substantially vertical path.
In an effort to alleviate the requirement of maintaining an actuated motor during a workout, the weightlifting industry enlisted the use of motor-clutch assemblies. For example, as shown in U.S. Pat. No. 5,314,394, two sets of chains are disposed on respective upper and lower sprockets. The lower sprockets are mounted onto a rotatable shaft operably connected to a motor through a clutch. An arm support assembly, which receives a barbell, is slidably mounted to vertical shafts and connected to the chains. While the lifter is exercising, the motor is not energized, allowing the shaft to freely spin as the arm support assembly moves along the vertical shafts. Once the lifter desires the device to lift the barbell, the lifter causes clutch to engage the shaft which permits the motor to controllably rotate the shaft and lift the barbell. However, the arm support assembly is not capable of providing xe2x80x9cfree-weightxe2x80x9d full range of motion. Additionally, the chains can not move around their respective sprockets independently of the other.
Thus, there remains a need for a free-weight device which self-spots a lifter with the benefit of an unactuated motor or winch. Further, there remains a need for a free-weight device which self-spots a lifter that provides independent reciprocating movement of a pair of cables which are securable from movement to support the weight of the weight assembly. In addition, there exists a need with such a device for a clutch which provides independent reciprocating movement of the cables which are operably connected to the motor. As well, there remains an need for such a device capable of varying the distance between the cables for various sized barbells or for the use of dumbbells. Still, there remains a need for such a device which is capable of securing the dumbbells for a free-weight workout by the lifter. Accordingly, it is to the provision of such that the present invention is primarily directed.
This invention overcomes the disadvantages of the prior art by providing a barbell and dumbbell safety spotting apparatus that is simple in design and construction, inexpensive to fabricate, and easy to use. The preferred embodiment of the apparatus comprises a frame, two booms supported by the frame, two cables respectively movably extending from the booms, two reciprocating drives respectively operably connected to the cables to provide reciprocating movement of the cables, a rotary pawl clutch operably reciprocating movement of the cables and a motor assembly capable of retracting and extending the cables. The cables are connectable to the barbell or the dumbbells and provide reciprocating movement thereto in free-weight fashion. The booms are pivotally mounted to the frame so that the distance between the cables is variable.
The reciprocating drive comprises an endless chain movably and operably extending about a rotatable sprocket gear and a rotatable drive shaft that is operably connected to the motor assembly, which is lockable to prevent rotation of the drive shaft. Counterweights are mounted to the chains to maintain tension on and assist in retracting the cables. The cables are respectively attached to the counterweights to prevent binding of the cables during reciprocating motion thereof or during pivotal movement of the booms. Independent reciprocating movement of each reciprocating drive is provided by operably connecting the respective chain to the drive shaft with the rotary pawl clutch.
The rotary pawl clutch comprises a pawl base, at least one pawl pivotally mounted to the pawl base for each reciprocation drive, a solenoid mounted to the pawl base for each pawl to actuate the pawl, and a ratchet-sprocket gear engagable with the pawl. The pawl base is fixedly mounted to and rotates with the drive shaft. The ratchet-sprocket gear has a ratchet wheel portion and a sprocket portion. The ratchet-sprocket gear is rotatably mounted on the drive shaft with the ratchet wheel portion adjacent the pawl base. The ratchet wheel portion has a plurality of substantially evenly spaced indentations along the circumference thereof which are removably engagable with the pawl to prevent both rotation of the ratchet-sprocket gear and movement of the chain such that the respective cable is prohibited from extending from the boom.
Dumbbells are suspendable from the respective cables by dumbbell clamps removably attached thereto. Each dumbbell clamp has a two spaced-apart plates mounted to one another and the plates are substantially identical in shape. The plates have a notch for receiving a grip of the dumbbell. An elongated slot intersects the notch, and a locking bar is slidably secured therein. A spring is disposed in each slot to bias the locking bar toward the notch to removably engage the grip, thereby securing the grip within the notch. It is to be understood that the phraseology and terminology employed herein are for the purpose of description and should not be regarded as limiting. As such, those skilled in the art will appreciate that the conception, upon which this disclosure is based, may readily be utilized as a basis for the designing of other structures, methods, and systems for carrying out the several purposes of the present invention. It is important, therefore, that the claims be regarded as including such equivalent constructions insofar as they do not depart from the spirit and scope of the present invention.
Other objects, advantages and capabilities of the invention will become apparent from the following description taken in conjunction with the accompanying drawings showing preferred embodiments of the invention.